In parts of Georgia and South Carolina, as soon as a group of girls are fairly out of the house for a morning’s play, one suddenly points the finger at a companion with the exclamation, “Green!” The child so accosted must then produce some fragment of verdure–the leaf of a tree, a blade of grass, etc.–from the apparel or else pay forfeit … It is rarely, therefore, that a child will go abroad without a bit of ‘green,’ the practice almost amounting to a superstition. The object of each is to make the rest believe that the required piece of verdure has been forgotten, and yet to keep it at hand.

When researchers dug a little deeper, they realized that they were seeing a version of a game that was unique to France, and popular from the 13th to 14th centuries. (It was even mentioned by Rabelais.)

Newell describes the original French game as one played by adults during Lent, after the singing of the Angelus. It went like this:

If any lady accost you and shows you her bough, you must immediately exhibit yours. If you have not such a one, or if your green is of a shade less rich than your adversary’s, you lose a point; in case of doubt, the matter is referred to an umpire.

The phrase said to the loser gave the game its name: “I catch you without green!” (“Je vous prends sans vert”).

The punishment for losing was to have a pail of water dumped over your head, or else a pay fine. (Money from the fines was supposedly deposited in a fund to provide a “merry repast” for the village.)

How did a medieval French game survive only in scattering of counties in the Carolinas from the Colonial period to at least the late 20th century?

Simple: some Huguenot families left France and settled in that region of America during the 18th century. The custom had survived in their region of France, and crossed the pond to take root in the New World. American culture and language are full of things that survived here after they faded away in their country of origin.